Backrest for use in a bathtub



FIG. 1 is a top plan view of a backrest for use in a bathtub showing my new design;

FIG. 2 is a side view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is an elevational view taken from one end thereof;

FIG. 5 is an elevational view taken from the end opposite that shown in FIG. 4; and

FIG. 6 is a perspective view thereof. 

The ornamental design for a backrest for use in a bathtub, as shown and described. 